Dishwasher and controlling method thereof

ABSTRACT

A dishwasher is provided. The dishwasher includes a tub, a steam generator, and a connecting passage. The tub stores dishes. The steam generator generates steam to be supplied into the tub. The connecting passage connects a discharging end of the steam generator to an inside of the tub.

TECHNICAL FIELD

The present invention relates to a dishwasher.

BACKGROUND ART

A dishwasher is a home appliance that sprays high-pressure wash liquidwithin a tub to wash and remove food residue and other impurities lefton surfaces of dishes. A filter filters the food residue from the washliquid to recycle the latter, and detergent is dissolved into the washliquid to facilitate the removal of food residue.

In order to improve the above dishwashing process, the followingdishwasher functions have been developed.

First, by heating wash liquid to aid in dissolving the detergent,overall dishwashing effectiveness can be improved. Also, by heating washliquid, the wash liquid can more easily remove glutinous rice and otherhardened food residue.

Furthermore, by dividing the wash cycle of a dishwasher into a pre-washcycle and a main wash cycle, the pre-wash cycle soaks hardened foodresidue, so that it can be more easily removed in the main wash cycle.

Another method being employed is removing germs and sterilizing dishesby emitting ultraviolet light onto the surfaces of dishes.

However, despite the above devised methods according to the related art,the problem of increasing dishwashing efficiency remains. Especially inoriental households, where in many cases, the staple food is glutinousrice, the latter is difficult to effectively remove from dishes,exasperating the problem of dishwashing efficiency. Even the use of hotwater to soak food residue cannot completely obviate the above problem.

Also, because soaking requires a prolonged amount of time, it lengthensthe duration of the wash cycle.

Furthermore, because a dishwasher is used repeatedly, food depositsaccumulate and harden on the inner surfaces of the tub, and a strongsmell is emitted when this hardened residue is contaminated by germs.Furthermore, even after dishes are washed, food residue and germs stillremain on them. Thus, the overall washing efficiency of a dishwasher isreduced.

Additionally, dishwashers according to the related art sprinkledetergent onto dishes after which they are rinsed by wash liquid. Thus,the detergent is inefficiently used.

Technical Problem

To solve the above problem, the present invention provides a dishwasherand a controlling method thereof that easily remove food depositshardened on dishes, increasing the efficiency of washing dishes.

Another object of the present invention is to provide a dishwasher and acontrolling method thereof that quickly soak food deposits on dishes, sothat the duration of the washing cycle of the dishwasher is reduced toprovide more convenience to a user.

A further object of the present invention is to provide a dishwasher anda controlling method thereof that improve the washing efficiency of thedishwasher.

A still further object of the present invention is to provide adishwasher and a controlling method thereof that increase surface activeefficiency of detergent, so that dishwashing efficiency increases.

Technical Solution

According to an aspect of the present invention, there is provided adishwasher including: a tub for storing dishes; a steam generator forgenerating steam to be supplied into the tub; and a connecting passagefor connecting a discharging end of the steam generator to an inside ofthe tub.

According to another aspect of the present invention, there is provideda controlling method of a dishwasher, including: preparing a dishwasherincluding a tub for storing dishes, a steam generator for generatingsteam to be supplied into the tub, and a connecting passage forconnecting a discharging end of the steam generator to an inside of thetub; supplying steam into the tub from the steam generator; and sprayingwash liquid onto the dishes.

According to a further aspect of the present invention, there isprovided a controlling method of a dishwasher, including: preparing adishwasher including a tub for storing dishes, a steam generator forgenerating steam to be supplied into the tub, and a connecting passagefor connecting a discharging end of the steam generator to an inside ofthe tub; supplying steam into the tub from the steam generator; sprayingwash liquid onto the dishes; spraying the wash liquid again anddetermining whether to repeat the supplying of the steam; andalternately repeating the spraying of the wash liquid and the supplyingof the steam when the determining determines to repeat the supplying ofthe steam.

According to an additional aspect of the present invention, there isprovided a controlling method of a dishwasher, including: preparing adishwasher including a tub for storing dishes, a steam generator forgenerating steam to be supplied into the tub, and a connecting passagefor connecting a discharging end of the steam generator to an inside ofthe tub; performing a main wash cycle through spraying wash liquid mixedwith detergent for washing the dishes; and supplying the steam from thesteam generator into the tub in at least one of a cycle before and afterthe main wash cycle.

ADVANTAGEOUS EFFECTS

An advantage of the dishwasher and controlling method thereof accordingto the present invention is that they can easily remove food residuehardened on dishes to improve washing efficiency of the dishwasher.

Another advantage of the dishwasher and controlling method thereofaccording to the present invention is that soaking of dishes isperformed quickly so that the duration of the dishwasher's washing cycleis reduced, thereby reducing the work performed by the pump and powerconsumption of the dishwasher.

A further advantage of the dishwasher and controlling method thereofaccording to the present invention is that they improve sterilizingefficiency of dishes for improved hygiene thereof.

A still further advantage of the dishwasher and controlling methodthereof according to the present invention is that they satisfactorilyclean dishes physically, chemically, and biologically at the same time,so that food residue can be more thoroughly removed from dishes.

An additional advantage of the dishwasher and controlling method thereofaccording to the present invention is that the spraying of wash liquidand then the supplying of steam is repeated, improving the cleanlinessof dishes.

Another added advantage of the dishwasher and controlling method thereofaccording to the present invention is that hot steam can be dischargedduring a plurality of cycles, so that the efficiency of the dishwasherincreases.

A further added advantage of the dishwasher and controlling methodthereof according to the present invention is that they increase thedissolving of detergent in wash liquid to increase the efficiency of thedishwasher.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a dishwasher according to the firstembodiment of the present invention.

FIG. 2 is a perspective view of a dishwasher according to the firstembodiment of the present invention with its door open.

FIG. 3 is a sectional view of the dishwasher in FIG. 1 taken along lineI-I′.

FIG. 4 is a flowchart showing a controlling method of a dishwasheraccording to the first embodiment of the present invention.

FIG. 5 is a flowchart showing a controlling method of a dishwasheraccording to the second embodiment of the present invention.

FIG. 6 is a flowchart showing a controlling method of a dishwasheraccording to the third embodiment of the present invention.

FIG. 7 is flowchart showing a controlling method of a dishwasheraccording to the fourth embodiment of the present invention.

FIG. 8 is flowchart showing a controlling method of a dishwasheraccording to the fifth embodiment of the present invention.

FIG. 9 is flowchart showing a controlling method of a dishwasheraccording to the sixth embodiment of the present invention.

FIG. 10 is flowchart showing a controlling method of a dishwasheraccording to the seventh embodiment of the present invention.

BEST MODE

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

FIG. 1 is a perspective view of a dishwasher according to the firstembodiment of the present invention.

Referring to FIG. 1, a dishwasher according to the present inventionincludes a case 1 forming an outer shape of the dishwasher and anopening at a front thereof, a door 2 sealing the opening at the front ofthe case 1, and a control panel 3 provided above the door 2, fordisplaying and controlling the operation of the dishwasher.

In detail, the control panel 3 includes a power switch 5 for switchingpower to the dishwasher on and off, a door handle 4 used to open andclose the door 2, controls 7 for implementing a predetermined operationof the dishwasher according to a user's inputted commands, and a display8 for displaying the operation of the dishwasher.

FIG. 2 is a perspective view of a dishwasher according to the firstembodiment of the present invention with its door open.

Referring to FIG. 2, a tub 18 for containing wash liquid inside thedishwasher is disposed therein, and a sump 16 disposed at the bottom ofthe tub 18 for collecting, filtering, and re-circulating wash liquid tobe sprayed.

In detail, the inside of the tub 18 includes an upper dish rack 11 and alower dish rack 12 for placing dishes in, and an upper spray arm 14 andtop spray nozzle 24 for spraying wash liquid towards the upper dish rack11, and a lower spray arm 15 for spraying wash liquid towards the lowerdish rack 12. The inner surfaces of the tub 18 have a rail 13 extendingfrom front to rear in order to slide the upper dish rack 11 thereon. Afilter 17 is disposed at the bottom of the tub 18 to filter impuritiesfrom wash liquid.

A wash liquid passage 19 is provided at an inner side surface of the tub18, for supplying wash liquid to the upper spray arm 14 and the topspray nozzle 24.

The door 2 is coupled to the case 1 through a hinge (not shown) at thebottom of the door 2, so that a user can pivot the door about the hingein an upward or downward direction. An exhaust fan 9 formed in apredetermined location on the door 2 can forcefully expel air frominside the tub 18 to the outside. Also, a detergent cup 10 for holding apredetermined amount of detergent supplied therein is formed in theinner surface of the door 2, and supplies that amount of detergentduring the operation of the dishwasher.

FIG. 3 is a sectional view of the dishwasher in FIG. 1 taken along lineI-I′.

Referring to FIG. 3, a dishwasher according to the present inventionfurther includes a water supply pipe 22 connecting the tub 18 and awater supply outside of the dishwasher to supply water into the tub 18,a water draining pipe 23 for draining wash liquid (that has been usedfor dishwashing and is contaminated), a steam generator 20 forgenerating steam and disposed below the tub 18, and a steam supply pipe21 for supplying the steam generated by the steam generator 20 to theinside of the tub 18.

In detail, the end of the steam supply pipe 21 in the tub 18 forms asteam discharger 26 for discharging steam therefrom at the bottom of thetub 18. The steam discharger 26 discharges steam from the bottom of thetub 18 upward. Thus, due to the rising characteristic of steam in air,the steam discharged from the steam supply pipe 21 can evenly permeatethroughout the entire of the tub 18.

A predetermined sealing member (not shown) seals the space between theouter perimeter of the end of the steam supply pipe 21 entering the tub18 and the hole in the tub 18 through which the steam supply pipe 21passes. In this way, wash liquid is prevented from leaking through thegap between the steam supply pipe 21 and the tub 18, and affectinginterior components.

The water supply pipe 22 branches in two. In order to regulate the flowof water passing through the branched water supply pipe 22, a tub waterregulating valve 40 and a steam water regulating valve 41, for openingand closing the water supply pipe 22, are formed on the respectivebranches. The tub water regulating valve 40 controls the flow of waterflowing to the tub, and the steam water regulating valve 41 controls theflow of water flowing to the steam generator 20.

The operation of the above-described dishwasher according to the presentinvention will now be briefly described.

In order to wash dishes, the door 2 is opened, and dishes are placed inthe upper and lower dish racks 11 and 12, after which the door 2 isclosed. Of course, before the door 2 is closed, a predetermined amountof detergent, rinse, etc. may be added to the detergent cup 10.

By manipulating the controls 7, when a user inputs desired controls andbegins the operation of the dishwasher, the display 8 displays theoperating status of the dishwasher.

When describing the operation of the dishwasher in terms of the flowsequence of wash liquid within the tub 18, wash liquid is firstdischarged from the upper and lower spray arms 14 and 15 and the topspray nozzle 24 to wash dishes in the upper and lower dish racks 11 and12, after which the wash liquid descends to the sump 16 below. Animpeller or other type of predetermined pump is installed in the sump16, to pressurize and re-supply the wash liquid to the spray arms 14 and15 and top spray nozzle 24. While the wash liquid circulates to thespray arms 14 and 15 and spray nozzle 24 from the sump 16, food residueis filtered by the filter 17 to prevent excessive contamination of thewash liquid and clogging of nozzles.

At a certain point during the above operation of the dishwasher, thesteam generated by the steam generator 20 passes through the steamsupply pipe 21 to be supplied into the tub 18. Thus, the hot and moistcharacteristics of the steam ameliorate the operational reliability andefficiency of the dishwasher.

Below, a controlling method, with respect to the operation of the steamgenerator 20 of a dishwasher according to the present invention, will begiven in detail.

Because steam is a gaseous form of boiled water that has hot and moistcharacteristics, it is suitable for improving washing efficiency of adishwasher. Steam is especially suitable for soaking food residue driedand hardened on dishes for easy removal, and its heat is suitable forsterilizing purposes.

FIG. 4 is a flowchart showing a controlling method of a dishwasheraccording to the first embodiment of the present invention.

Referring to FIG. 4, before dishes are placed inside the dishwasher andthe dishwasher is operated, water present in the dishwasher is firstdrained in an initial draining in step S1.

After the initial draining is completed, the steam generator 20 isoperated and supplies steam into the tub 18 in step S2. The supplying ofsteam in step S2 is performed over a certain duration, and may beperformed for a duration in which hardened food residue is adequatelysoaked. The steam may be supplied continuously into the tub 18 for atleast a predetermined duration. The duration of supplying steam may bepreset or automatically controlled. For example, when dirty dishes areput into the dishwasher after sitting for a long time, a user may entera setting that supplies steam over a longer duration, so that thehardened food deposits have enough time to soften.

After the food deposits are adequately soaked, in step S2 of supplyingsteam, wash liquid is supplied and sprayed toward the dishes by thelower and upper spray arms 14 and 15 and the top spray nozzle 24. Thewash liquid sprayed through the spray arms and nozzle in step S3 may besprayed at a lower pressure than normal and still easily remove fooddeposits that have already been softened by the steam.

After the dishes are washed to a certain extent of food deposits by thesprayed wash liquid, wash liquid supplied with detergent is sprayed tochemically remove grease from the dishes in step S4. This washing ofdishes using wash water with detergent can be referred to as a main washcycle, and the washing without using detergent can be referred to as apre-wash cycle.

When the pre-wash and main wash cycles are completed, fresh wash liquidis supplied and sprayed to perform a rinse cycle in step S5. The rinsecycle may be repeated a number of times, depending on the condition ofthe dishes.

After the rinse cycle is completed, cool or hot air is forcibly blown toperform a drying cycle in step S6.

When the drying cycle is completed, a cycle for storing dishes isperformed.

As described, the controlling method of a dishwasher according to thepresent invention performs a cycle of supplying steam to soak foodresidue before performing the wash cycle in which wash liquid is sprayedonto dishes. In this way, wash liquid sprayed at a lower pressure ismore than adequate for washing dishes of food residue. Because foodresidue can be washed using low pressure spray, the work performed bythe pump to pressurize wash liquid can reduced.

Because food deposits are washed after being soaked, extra time isrequired to supply the steam; however, because the duration of sprayingwash liquid is reduced, the entire course of the dishwasher consumesless time overall.

Food deposits that are hardened on dishes can be easily removed in thisembodiment, so that the washing efficiency of dishes improves.

Also, because soaking is performed quickly, the dishwashing course takesless time, and the work performed by the pump is reduced, thereby savingenergy.

MODE FOR INVENTION

Alternative embodiments according to the present invention will bedescribed below. Descriptions of like parts already described in thefirst embodiment shall be deemed included herein, and are thereforeomitted herefrom.

FIG. 5 is a flowchart showing a controlling method of a dishwasheraccording to the second embodiment of the present invention.

Referring to FIG. 5, after dishes are stored inside the dishwasher, theoperation of the dishwasher is begun. Prior to this, water already inthe unit undergoes an initial draining in step S11. After the initialdraining has been performed, wash liquid is supplied and sprayed towardsthe dishes through the lower and upper spray arms 14 and 15 and the topspray nozzle 24.

During the spraying of wash liquid, larger food particles are washed instep S12. This wash cycle, which is not supplied with detergent, washesfood residue using only wash liquid, and can therefore be called apre-wash cycle.

After the pre-washing in step S12 is completed, steam is supplied intothe tub in step S13. The supplying of steam in step S13 is sustained fora predetermined duration, which may extend for a period suitable tocompletely soak the deposits hardened on the dishes. The steam iscontinuously consumed inside the tub 18, and may be suppliedcontinuously for at least a predetermined duration. Also, the durationfor supplying the steam may be preset or automatically determined. Forexample, when dirty dishes are put into the dishwasher after sitting fora long time, a user may enter a setting that supplies steam over alonger duration, so that the hardened food deposits have enough time tosoften. This process may be referred to as a soaking steam supplyingstage because the food deposits are soaked.

The soaking steam supplying stage in step S13 soaks the food deposits,after which a main wash cycle is performed using wash liquid mixed withdetergent in step S14. The main wash cycle may be performed repeatedlyseveral times depending on the state of the dishwasher operation.

Even when the wash liquid that is sprayed through the spray arms andnozzle during the main wash cycle is sprayed at a lower pressure, it caneasily clean the dishes because the dishes have already been soaked inthe steam.

After the main wash cycle is performed, a draining cycle of the washliquid is performed in step S15, after which steam is supplied in stepS16. Here, the hot steam that is supplied contacts the surfaces of thedishes and kills germs thereon, thus performing sterilizing.

The steam supplied in step S16 may be controlled, based on the quantityand types of dishes stored, and a user's direct input. For example, whenitems such as wash cloths and cutting boards that require a longersterilizing time are being sterilized, a longer sterilizing setting maybe inputted. Because hot steam is used for sterilizing in step S16, thisstage may be referred to as a sterilizing steam supplying stage.

After the sterilizing steam supplying stage in step S16 is performed,fresh wash liquid is supplied and sprayed to perform a rinse cycle instep S17. The rinse cycle may be repeated several times, depending onthe condition of the dishes.

After the rinse cycle is completed, cool or hot air is blown to performa drying cycle in step S18.

After the drying is completed, a storage cycle is performed.

As described, the controlling method of a dishwasher according to thepresent invention supplies steam after the main wash cycle is completed,so that germs that may be present on the surfaces of dishes are killed,thereby increasing the level of sanitation of the dishes. In particular,steam is supplied in the stage before the rinsing cycle to performsterilization, so that the removed germs can be discharged to theoutside along with the wash liquid. Moreover, because steam is suppliedagain, the soaking of food residue is more efficient.

In another embodiment, the soaking steam supplying in step S13 and thesterilizing steam supplying in step S16 may be selectively performedaccording to specific operating conditions, in order to prevent oversupplying of steam and energy waste.

In this embodiment, sterilizing efficiency is improved so that thesanitation of dishes increases.

FIG. 6 is a flowchart showing a controlling method of a dishwasheraccording to the third embodiment of the present invention.

Referring to FIG. 6, dishes are stored within the dishwasher, afterwhich the dishwasher is activated. Prior to this, water already in theunit undergoes an initial draining in step S21. After the initialdraining has been performed, wash liquid is supplied and sprayed towardsthe dishes through the lower and upper spray arms 14 and 15 and the topspray nozzle 24.

During the spraying of wash liquid, larger food particles are washed instep S22. This wash cycle, which is not supplied with detergent, washesfood residue using only wash liquid, and can therefore be called apre-wash cycle.

After the pre-washing in step S22 is completed, steam is supplied intothe tub 18 in step S33. The supplying of steam in step S23 is sustainedfor a predetermined duration, which may extend for a period suitable tocompletely soak the deposits hardened on the dishes. The steam iscontinuously consumed inside the tub 18, and may be suppliedcontinuously for at least a predetermined duration. Also, the durationfor supplying the steam may be preset or automatically determined. Forexample, when dirty dishes are put into the dishwasher after sitting fora long time, a user may enter a setting that supplies steam over alonger duration, so that the hardened food deposits have enough time tosoften.

The soaking steam supplying stage in step S23 soaks the food deposits,after which a determining of whether to repeatedly perform the sprayingof wash liquid in step S22 and the supplying of steam in step S23, basedon the turbidity of the wash liquid and/or the stage of the wash courseand/or a user's direct input, is performed in step S24.

If it is determined in step S24 that previous steps should be repeated,the spraying of wash liquid in step S22 and the supplying of steam instep S23 is repeatedly performed. Of course, after steps S22 and S23 areboth repeated once, step S24 is again performed to determine whether torepeat the steps again. Furthermore, by adding detergent to the sprayedwash liquid in at least one of the repetitions of step S22 during therepeated performing of steps S22 and S23, the wash liquid may be sprayedwith detergent mixed therein, so that it can completely clean greasefrom the dishes. Also, the wash liquid may be drained at a point duringthe repeating cycles, according to the condition of the wash liquid.

The number of repeated cycles may be varied according to relevantconditions. For example, if glutinous rice should be hardened and stuckfirmly on the dishes, requiring a vigorous wash cycle, a plurality ofspraying cycles of wash liquid may be implemented without usingdetergent.

Additionally, when it is determined in step S24 that the repeated cyclesare no longer needed, steam is again supplied in step S25 to completelysterilize the dishes. Fresh rinse water is sprayed on the dishes in arinse cycle in step S26, and cool or hot air is supplied in step S27 infor drying. The repeated supplying of steam in step S25 may selectivelybe performed as required.

The steam supplied by the controlling method of a dishwasher accordingto the present invention may be varied, based on the quantity and typesof dishes stored, and a user's direct input. For example, when itemssuch as wash cloths and cutting boards that require a longer sterilizingtime are being sterilized, a longer sterilizing setting may be inputted.It also follows that the larger the quantity of dishes, the longer thesterilizing may be performed.

As described, the controlling method of a dishwasher according to thepresent invention continuously supplies steam after the spraying of washliquid is completed (in other words, the supplying of steam isalternately performed with the spraying of wash liquid), therebyincreasing the level of sanitation of the dishes. That is to say, thesupplying of steam soaks food residue to increase the cleanliness of thedishes from a physical standpoint. In the stage prior to the rinse cyclein step S26, steam is supplied once more to further sterilize thedishes.

FIG. 7 is flowchart showing a controlling method of a dishwasheraccording to the fourth embodiment of the present invention.

Referring to FIG. 7, dishes are stored within the dishwasher, afterwhich the dishwasher is activated. Prior to this, water already in theunit undergoes an initial draining in step S31. After the initialdraining has been performed, wash liquid is supplied and sprayed towardsthe dishes through the lower and upper spray arms 14 and 15 and the topspray nozzle 24.

During the spraying of wash liquid, larger food particles are washed instep S32. This wash cycle, which is not supplied with detergent, washesfood residue using only wash liquid, and can therefore be called apre-wash cycle.

After the pre-washing in step S32 is completed, steam is supplied intothe tub 18 in step S33. The supplying of steam in step S33 is performedby supplying the steam generated by the steam generator 20 through thesteam supply pipe 21 into the tub 18. The supplying of steam in step S33is sustained for a predetermined duration, which may extend variably,depending on the quantity and state of cleanliness of dishes stored inthe tub 18. For example, a setting that supplies steam over a longerduration may be used for glutinous rice that is hardened and stuck ondishes.

After the supplying of steam in step S33, fresh wash liquid withdetergent mixed therein is supplied and sprayed into the tub 18 in amain wash cycle in step S34.

After the supplying of steam in step S33 and the spraying of wash liquidin step S34 soaks food deposits to a certain degree, it is determined instep S35 whether to repeat steps S34 and S33, according to the washcourse settings and/or a user's inputs. Thus, the repeated number oftimes that wash liquid is sprayed in step S34 and steam is supplied instep S33 is compared to a preset number, and if the numbers are unequal,the steps S34 and S33 are repeated.

Because the time that food residue soaks lengthens as the number ofspraying repetitions of wash liquid increases in the main wash cycle,the amount of food residue remaining on dishes decreases. Moreover,because food deposits hardened on dishes are softened during thesupplying of steam in step S33, the food deposits can be completelyremoved.

By alternating and repeating the spraying of wash liquid in step S34 andthe supplying of steam in S33, food residue can be more reliablyremoved, thereby increasing the cleaning efficiency of dishes.

After the main wash cycle is completed, the wash liquid is drained instep S36, a rinse cycle is performed in step S37 using clean water, anda drying cycle is performed in step S38 using cool or hot blown air.

The steam supplied by the controlling method of a dishwasher accordingto the present invention may be varied, based on the quantity and typesof dishes stored, and a user's direct input. For example, the larger thequantity of dishes, the more steam should be supplied.

As described, the controlling method of a dishwasher according to thepresent invention continuously sprays wash liquid and supplies steam inthe main wash cycle. That is to say, the supplying of steam soaks foodresidue to increase the cleanliness of the dishes from a physicalstandpoint. Furthermore, because the wash liquid spraying and steamsupplying are alternatingly repeated, the dishes are cleaned that muchmore efficiently.

FIG. 8 is flowchart showing a controlling method of a dishwasheraccording to the fifth embodiment of the present invention.

Referring to FIG. 8, dishes are stored within the dishwasher, afterwhich the dishwasher is activated. Prior to this, water already in theunit undergoes an initial draining in step S41. After the initialdraining has been performed, steam is supplied into the tub 18 in stepS42. The supplying of steam in step S42 is performed by supplying thesteam generated by the steam generator 20 through the steam supply pipe21 into the tub 18. The supplying of steam in step S42 is sustained fora predetermined duration, which may extend variably, depending on thequantity and state of cleanliness of dishes stored in the tub 18. Forexample, a setting that supplies steam over a longer duration may beused for glutinous rice that is hardened and stuck on dishes.

After the steam is supplied over a certain duration, wash liquid issupplied and sprayed towards the dishes through the lower and upperspray arms 14 and 15 and the top spray nozzle 24. During the spraying ofwash liquid, larger food particles are washed in step S43. This washcycle, which is not supplied with detergent, washes food residue usingonly wash liquid, and can therefore be called a pre-wash cycle.

After a one-time supplying of steam in step S42 that soaks food depositsto a certain degree and the spraying of wash liquid in step S43, it isdetermined in step S44 whether to repeat steps S43 and S42, according tothe wash course settings and/or a user's inputs. The number of times thespraying of wash liquid in step S43 and the supplying of steam in S42are repeated is compared to a preset number, and if the numbers areunequal, the steps S43 and S42 are repeated.

Because the time that food residue soaks lengthens as the number ofspraying repetitions of wash liquid increases in the main wash cycle,the amount of food residue remaining on dishes decreases. Moreover,because food deposits hardened on dishes are softened during thesupplying of steam in step S42, the food deposits can be completelyremoved.

By alternating and repeating the spraying of wash liquid in step S43 andthe supplying of steam in step S42, food residue can be more reliablyremoved, thereby increasing the cleaning efficiency of dishes.

Next, when the preset number equals the number of repetitions, thepre-wash cycle ends, and wash liquid with detergent mixed therein issprayed in the main wash cycle in step S45. After the main wash cycle iscompleted, fresh rinsing water is sprayed on the dishes in a rinse cyclein step S46, and then a drying cycle is implemented in step S47 usingcool or hot blown air.

The steam supplied by the controlling method of a dishwasher accordingto the present invention may be varied, based on the quantity and typesof dishes stored, and a user's direct input. For example, the larger thequantity of dishes, the more steam should be supplied.

As described, the controlling method of a dishwasher according to thepresent invention supplies steam in a prewash cycle and sprays washliquid, alternating the two steps. That is to say, because the washliquid spraying and steam supplying are alternatingly repeated, thedishes are cleaned that much more efficiently.

That is to say, the supplying of steam soaks food residue to increasethe cleanliness of the dishes from a physical standpoint. Furthermore,because the wash liquid spraying and steam supplying are alternatinglyrepeated, the dishes are cleaned that much more efficiently.

FIG. 9 is flowchart showing a controlling method of a dishwasheraccording to the sixth embodiment of the present invention.

Referring to FIG. 9, dishes are stored within the dishwasher, afterwhich the dishwasher is activated. Prior to this, water already in theunit undergoes an initial draining in step S51. After the initialdraining has been performed, steam is supplied into the tub 18 in stepS52. The supplying of steam in step S52 is performed by supplying thesteam generated by the steam generator 20 through the steam supply pipe21 into the tub 18. The supplying of steam in step S52 is sustained fora predetermined duration, which may extend variably, depending on thequantity and state of cleanliness of dishes stored in the tub 18. Forexample, a setting that supplies steam over a longer duration may beused for glutinous rice that is hardened and stuck on dishes.

After the steam is supplied over a certain duration in step S52, washliquid is sprayed in step S53 towards the dishes. Even when the washliquid is sprayed at a lower pressure, it can easily remove food residuethat has already been soaked by the steam.

After a one-time supplying of steam in step S52 and a spraying of washliquid in step S53, it is determined in step S54 whether to repeat stepsS53 and S52, according to the wash course settings and/or a user'sinputs. The number of times the spraying of wash liquid in step S53 andthe supplying of steam in S52 are repeated is compared to a presetnumber, and if the numbers are unequal, steps S53 and S52 are repeated.

Because the time that food residue soaks lengthens as the number ofspraying repetitions of wash liquid increases in the main wash cycle,the amount of food residue remaining on dishes decreases. Moreover,because food deposits hardened on dishes are softened during thesupplying of steam in step S52, the food deposits can be completelyremoved.

By alternating and repeating the spraying of wash liquid in step S53 andthe supplying of steam in S52, food residue can be more reliablyremoved, thereby increasing the cleaning efficiency of dishes.

Furthermore, by adding detergent to the sprayed wash liquid in at leastone of the repetitions of step S53 during the repeated performing ofsteps S52 and S53, the wash liquid may be sprayed with detergent mixedtherein, so that it can completely clean grease from the dishes.

At least one rinse cycle without using detergent may be performed duringthe repeating wash liquid spraying in step S53 and the supplying ofsteam in step S52 as a final rinsing cycle, in order to preventdetergent from remaining on dishes.

After the number of repetitions is determined to be equal to a presetnumber and the spraying of the wash liquid is ended, cool or hot air issupplied in a drying cycle in step S55.

The steam supplied by the controlling method of a dishwasher accordingto the present invention may be varied, based on the quantity and typesof dishes stored, and a user's direct input. For example, the larger thequantity of dishes, the more steam should be supplied.

As described, the controlling method of a dishwasher according to thepresent invention supplies steam to soak food residue and sprays washliquid, alternating the two steps. That is to say, because the washliquid spraying and steam supplying are alternatingly repeated, thedishes are cleaned that much more efficiently. In other words, thesupplying of steam soaks food residue to allow easy washing of theresidue from dishes, and sterilizes germs on the surfaces of dishesthrough the hot steam.

The supplying of steam soaks food deposits and increase the cleanlinessof the dishes from a physical standpoint. Furthermore, because the washliquid spraying and steam supplying are alternatingly repeated, thedishes are cleaned that much more efficiently.

Also, because hot steam can be discharged in multiple cycles, thesterilizing effect of dishes is ameliorated.

FIG. 10 is flowchart showing a controlling method of a dishwasheraccording to the seventh embodiment of the present invention.

Referring to FIG. 10, dishes are stored within the dishwasher, afterwhich the dishwasher is activated. Prior to this, water already in theunit undergoes an initial draining in step S61.

After the initial draining has been performed, a pre-wash cycle isperformed in step S62. The pre-wash cycle in step S62 is a cycle thatuses water without detergent mixed in to wash comparatively large foodparticles from dishes.

After the pre-wash cycle is ended, the wash liquid is drained, and freshwash liquid is supplied and mixed with detergent in step S63. Thedetergent is sprayed with the wash liquid onto the dishes, and steam issupplied to activate the detergent in step S64. Steam is supplied intothe tub 18 and contacts the detergent, activating the detergent. Theamount of steam supplied to the tub 18 may be adjusted depending on thecleanliness of dishes and other factors. For example, in the case ofdishes with lots of grease on their surfaces, the duration of supplyingsteam may be extended. Needless to say, the steam may be supplied in thetub for a preset duration.

When the steam is supplied over a predetermined duration, the detergentis activated, and wash liquid is sprayed in step S66, eliminatingimpurities. Here, because the detergent has been activated, the dishescan be cleaned more thoroughly.

After the pre-wash cycle and the main wash cycle are completed, the washliquid is drained in step S67, and fresh wash liquid is supplied andsprayed to perform a rinse cycle in step S68. The rinse cycle may beperformed a plurality of times, depending on the state of the dishes.

When the rinse cycle is ended, cool or hot air is forcibly blown toperform a drying cycle in step S69.

When the drying cycle ends, a storing cycle of the dishes isimplemented.

As described, the controlling method of a dishwasher according to thepresent invention discharges steam into the tub 18 over a predeterminedduration after detergent is sprayed on dishes. Because the steamactivates the detergent on the dishes, the dishwashing efficiencyincreases.

Because soaking of food deposits can be performed by supplying steam,even when the wash liquid is sprayed at a lower pressure, it sufficesfor washing deposits off the dishes. Because wash liquid sprayed at alower pressure is able to remove food deposits, the pump pressurizingthe wash liquid does not have to perform as much work.

Because washing is performed after food residue is soaked, the processof supplying steam takes more time; however, due to the time of sprayingwash liquid being shortened as a result, the overall duration of a washcourse can be shortened.

Also, the hot steam acts to sterilize dishes.

A further embodiment according to the present invention does not spraywash liquid with detergent before supplying steam, but supplies steamfor a predetermined period first in order to activate the detergent. Theimportant factor is how long steam is supplied after detergent isdeposited on the dishes.

While the present invention has been described and illustrated hereinwith reference to the preferred embodiments thereof, it will be apparentto those skilled in the art that various modifications and variationscan be made therein without departing from the spirit and scope of theinvention. Thus, it is intended that the present invention covers themodifications and variations of this invention that come within thescope of the appended claims and their equivalents.

INDUSTRIAL APPLICABILITY

The dishwasher and the controlling method thereof according to thepresent invention improve dishwashing efficiency, reduce energyconsumption, and improve sanitation of dishes, for a high industrialapplicability.

1. A dishwasher comprising: a tub for storing dishes; a steam generatorfor generating steam to be supplied into the tub; and a connectingpassage for connecting a discharging end of the steam generator to aninside of the tub.
 2. The dishwasher according to claim 1, wherein anend of the connecting passage connected to the inside of the tub isformed at a bottom portion of the tub.
 3. The dishwasher according toclaim 1, wherein an end portion of the connecting passage connected tothe inside of the tub is sealed against the tub.
 4. The dishwasheraccording to claim 1, wherein the connecting passage discharges steamfrom a bottom to a top of the tub.
 5. The dishwasher according to claim1, wherein the steam soaks impurities deposited on the dishes.
 6. Thedishwasher according to claim 5, wherein the steam performs a soaking ofimpurities on the dishes, after which wash liquid is sprayed on thedishes to wash the dishes.
 7. The dishwasher according to claim 1,wherein the steam generator supplies the steam in at least one of acycle before and after a main cycle in which wash liquid mixed withdetergent is sprayed onto the dishes.
 8. The dishwasher according toclaim 1, wherein the steam generator supplies steam into the tub atleast two times with a predetermined interval therebetween.
 9. Thedishwasher according to claim 1, wherein the dishwasher performs a mainwash cycle that alternately implements a steam supplying cycle forsupplying steam into the tub and a wash liquid spraying cycle forspraying wash liquid mixed with detergent onto the dishes.
 10. Thedishwasher according to claim 9, wherein the main wash cycle is repeateda plurality of times.
 11. The dishwasher according to claim 1, whereinthe dishwasher performs a pre-wash cycle that alternately implements asteam supplying cycle for supplying steam into the tub and a wash liquidspraying cycle for spraying wash liquid that is not mixed with detergentonto the dishes.
 12. The dishwasher according to claim 11, wherein thepre-wash cycle is repeated a plurality of times.
 13. The dishwasheraccording to claim 1, wherein the dishwasher alternately performs asteam supplying cycle for supplying the steam into the tub and a washliquid spraying cycle for spraying wash liquid onto the dishes.
 14. Thedishwasher according to claim 1, wherein the steam generator suppliessteam into the tub for a predetermined duration when wash liquid mixedwith detergent is deposited on the dishes.
 15. A controlling method of adishwasher, comprising: preparing a dishwasher including a tub forstoring dishes, a steam generator for generating steam to be suppliedinto the tub, and a connecting passage for connecting a discharging endof the steam generator to an inside of the tub; supplying steam into thetub from the steam generator; and spraying wash liquid onto the dishes.16. The controlling method according to claim 15, wherein the supplyingof the steam into the tub is performed for soaking impurities depositedon the dishes, after which the spraying of the wash liquid onto thedishes is performed.
 17. The controlling method according to claim 16,wherein the spraying of the wash liquid includes spraying wash liquidthat is not mixed with detergent and spraying wash liquid that is mixedwith detergent.
 18. The controlling method according to claim 17,wherein the spraying of the wash liquid that does include the detergentis performed after the spraying of the wash liquid that does not includethe detergent.
 19. The controlling method according to claim 15, furthercomprising drying of the dishes after the supplying of the steam and thespraying of the wash liquid.
 20. The controlling method according toclaim 15, wherein the supplying of the steam into the tub fills the tubwith the steam when the dishes are deposited with detergent through thespraying of the wash liquid.
 21. The controlling method according toclaim 20, wherein the filling of the tub with the steam continues over apredetermined duration.
 22. The controlling method according to claim20, further comprising a further spraying of wash liquid after thefilling of the tub with the steam.
 23. The controlling method accordingto claim 15, wherein the steam supplied in the supplying of the steam isquantitively variable.
 24. A controlling method of a dishwasher,comprising: preparing a dishwasher including a tub for storing dishes, asteam generator for generating steam to be supplied into the tub, and aconnecting passage for connecting a discharging end of the steamgenerator to an inside of the tub; supplying steam into the tub from thesteam generator; spraying wash liquid onto the dishes; spraying the washliquid again and determining whether to repeat the supplying of thesteam; and alternately repeating the spraying of the wash liquid and thesupplying of the steam when the determining determines to repeat thesupplying of the steam.
 25. The controlling method according to claim24, wherein the alternating repeating of the spraying of the wash liquidand the supplying of the steam is continued.
 26. The controlling methodaccording to claim 24, wherein the supplying of the steam is implementeda final time, when the determining determines not to repeat thesupplying of the steam.
 27. The controlling method according to claim24, wherein the determining of whether to repeat the supplying of thesteam is based on at least one of a turbidity of the wash liquid, a washcourse status, and a selection of a user.
 28. The controlling methodaccording to claim 24, wherein the spraying of the wash liquid includesa spraying of wash liquid that is not mixed with detergent and aspraying of wash liquid that is mixed with detergent.
 29. Thecontrolling method according to claim 24, wherein the spraying of thewash liquid is performed after the supplying of the steam into the tuband impurities on the dishes have been soaked.
 30. A controlling methodof a dishwasher, comprising: preparing a dishwasher including a tub forstoring dishes, a steam generator for generating steam to be suppliedinto the tub, and a connecting passage for connecting a discharging endof the steam generator to an inside of the tub; performing a main washcycle through spraying wash liquid mixed with detergent for washing thedishes; and supplying the steam from the steam generator into the tub inat least one of a cycle before and after the main wash cycle.
 31. Thecontrolling method according to claim 30, wherein the supplying of thesteam is performed in the cycle before the main wash cycle, for soakingimpurities deposited on the dishes.
 32. The controlling method accordingto claim 30, wherein the supplying of the steam is performed in thecycle after the main wash cycle, for sterilizing the dishes.
 33. Thecontrolling method according to claim 30, further comprising a pre-washcycle including supplying the steam into the tub for soaking fooddeposits on the dishes, and spraying wash liquid that is not mixed withdetergent onto the dishes, the pre-wash cycle performed before the mainwash cycle.
 34. The controlling method according to claim 33, whereinthe pre-wash cycle alternately performs the supplying of the steam andthe spraying of the wash liquid.
 35. The controlling method according toclaim 34, wherein the pre-wash cycle is repeated until a number ofrepetitions thereof reaches a predetermined set number.
 36. Thecontrolling method according to claim 30, wherein the main wash cycleincludes supplying the steam into the tub.
 37. The controlling methodaccording to claim 30, wherein the main wash cycle is repeated until anumber of repetitions thereof reaches a predetermined set number. 38.The controlling method according to claim 30, further comprising rinsingthe dishes after a final stage of the main wash cycle.